patch 8.2.1161: Vim9: using freed memory
Problem: Vim9: using freed memory.
Solution: Put pointer back in evalarg instead of freeing it.
diff --git a/src/eval.c b/src/eval.c
index 68fb9cd..6a1bc4c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -379,10 +379,17 @@
* Skip over an expression at "*pp".
* If in Vim9 script and line breaks are encountered, the lines are
* concatenated. "evalarg->eval_tofree" will be set accordingly.
+ * "arg" is advanced to just after the expression.
+ * "start" is set to the start of the expression, "end" to just after the end.
+ * Also when the expression is copied to allocated memory.
* Return FAIL for an error, OK otherwise.
*/
int
-skip_expr_concatenate(char_u **start, char_u **end, evalarg_T *evalarg)
+skip_expr_concatenate(
+ char_u **arg,
+ char_u **start,
+ char_u **end,
+ evalarg_T *evalarg)
{
typval_T rettv;
int res;
@@ -398,12 +405,14 @@
if (ga_grow(gap, 1) == OK)
++gap->ga_len;
}
+ *start = *arg;
// Don't evaluate the expression.
if (evalarg != NULL)
evalarg->eval_flags &= ~EVAL_EVALUATE;
- *end = skipwhite(*end);
- res = eval1(end, &rettv, evalarg);
+ *arg = skipwhite(*arg);
+ res = eval1(arg, &rettv, evalarg);
+ *end = *arg;
if (evalarg != NULL)
evalarg->eval_flags = save_flags;
@@ -419,7 +428,7 @@
else
{
char_u *p;
- size_t endoff = STRLEN(*end);
+ size_t endoff = STRLEN(*arg);
// Line breaks encountered, concatenate all the lines.
*((char_u **)gap->ga_data) = *start;
@@ -428,7 +437,14 @@
// free the lines only when using getsourceline()
if (evalarg->eval_cookie != NULL)
{
+ // Do not free the first line, the caller can still use it.
*((char_u **)gap->ga_data) = NULL;
+ // Do not free the last line, "arg" points into it, free it
+ // later.
+ vim_free(evalarg->eval_tofree);
+ evalarg->eval_tofree =
+ ((char_u **)gap->ga_data)[gap->ga_len - 1];
+ ((char_u **)gap->ga_data)[gap->ga_len - 1] = NULL;
ga_clear_strings(gap);
}
else
@@ -437,8 +453,8 @@
if (p == NULL)
return FAIL;
*start = p;
- vim_free(evalarg->eval_tofree);
- evalarg->eval_tofree = p;
+ vim_free(evalarg->eval_tofree_lambda);
+ evalarg->eval_tofree_lambda = p;
// Compute "end" relative to the end.
*end = *start + STRLEN(*start) - endoff;
}
@@ -1936,7 +1952,7 @@
((char_u **)gap->ga_data)[gap->ga_len] = line;
++gap->ga_len;
}
- else
+ else if (evalarg->eval_cookie != NULL)
{
vim_free(evalarg->eval_tofree);
evalarg->eval_tofree = line;
@@ -1962,25 +1978,31 @@
}
/*
- * After using "evalarg" filled from "eap" free the memory.
+ * After using "evalarg" filled from "eap": free the memory.
*/
void
clear_evalarg(evalarg_T *evalarg, exarg_T *eap)
{
- if (evalarg != NULL && evalarg->eval_tofree != NULL)
+ if (evalarg != NULL)
{
- if (eap != NULL)
+ if (evalarg->eval_tofree != NULL)
{
- // We may need to keep the original command line, e.g. for
- // ":let" it has the variable names. But we may also need the
- // new one, "nextcmd" points into it. Keep both.
- vim_free(eap->cmdline_tofree);
- eap->cmdline_tofree = *eap->cmdlinep;
- *eap->cmdlinep = evalarg->eval_tofree;
+ if (eap != NULL)
+ {
+ // We may need to keep the original command line, e.g. for
+ // ":let" it has the variable names. But we may also need the
+ // new one, "nextcmd" points into it. Keep both.
+ vim_free(eap->cmdline_tofree);
+ eap->cmdline_tofree = *eap->cmdlinep;
+ *eap->cmdlinep = evalarg->eval_tofree;
+ }
+ else
+ vim_free(evalarg->eval_tofree);
+ evalarg->eval_tofree = NULL;
}
- else
- vim_free(evalarg->eval_tofree);
- evalarg->eval_tofree = NULL;
+
+ vim_free(evalarg->eval_tofree_lambda);
+ evalarg->eval_tofree_lambda = NULL;
}
}